Nailfold Videocapillaroscopy in Pediatric Rheumatology: Established Roles, Emerging Applications, and Future Perspectives.

Nailfold videocapillaroscopy (NVC) provides direct, non-invasive access to the peripheral microcirculation and has become a central tool in adult rheumatology. Its primary clinical value lies in the evaluation of patients presenting with signs of Raynaud phenomenon (RP) and scleroderma-spectrum disorders. In particular, NVC facilitates the differentiation between primary and secondary (scleroderma-related) RP. The characteristic scleroderma pattern observed on NVC, including giant capillaries, capillary loss, microhemorrhages, and architectural disorganization, supports the diagnosis of scleroderma-spectrum disorders. International standardization efforts have further improved the reliability and interpretability of these findings, particularly in adult populations with RP and systemic sclerosis (SSc). In children, the clinical utility of NVC is now well established for similar indications; however, interpretation requires age-specific reference data. Pediatric capillary density, diameter, and length vary throughout childhood, and minor findings such as tortuosity, crossing, and isolated microhemorrhages may also be observed in healthy individuals. Without normative pediatric data, these features may be overinterpreted as pathological findings. Beyond RP and juvenile SSc, evidence supporting the use of NVC is accumulating across a range of pediatric rheumatic diseases. NVC abnormalities have been reported in juvenile dermatomyositis (JDM), mixed connective tissue disease, childhood-onset systemic lupus erythematosus, juvenile Sjögren disease, and juvenile localized scleroderma. Among these conditions, JDM demonstrates the strongest association between NVC abnormalities-including reduced capillary density, dilatation, abnormal morphology, and microhemorrhages-and disease activity. In contrast, findings in juvenile idiopathic arthritis remain non-specific. More recent studies involving pediatric patients with Behçet disease, psoriatic arthritis, and certain autoinflammatory and vasculitic disorders suggest that NVC may detect subtle microvascular alterations; however, disease-specific patterns have not been established outside the scleroderma spectrum. Selected non-rheumatologic conditions, particularly diabetes mellitus, severe acute respiratory syndrome coronavirus 2 infection, multisystem inflammatory syndrome in children, and long coronavirus disease, further highlight the potential of NVC to reflect systemic endothelial dysfunction and non-specific microvascular injury, although these applications remain exploratory. Despite its promise, several limitations continue to restrict the broader clinical application of NVC. Pediatric reference data remain heterogeneous, scoring systems are largely adapted from adult protocols, and longitudinal evidence linking capillaroscopic changes to disease progression, treatment response, or long-term outcomes remains limited. Standardized image acquisition and reporting, multicenter cohort studies, and validation of automated image-analysis techniques are essential next steps for translating descriptive observations into clinically actionable information. This review summarizes the contribution of NVC to pediatric rheumatology and explores potential areas for future expansion. The strongest indications remain RP and scleroderma-spectrum disorders, whereas the most promising emerging application is in JDM, where microvascular changes correlate with disease activity. Across other pediatric rheumatic diseases, NVC currently serves as a complementary descriptive tool for vascular phenotyping rather than a standalone diagnostic modality. With the development of age-specific reference standards, harmonized protocols, and longitudinal validation studies, NVC has the potential to evolve from a descriptive imaging technique into an integral component of risk stratification and disease monitoring in pediatric rheumatology.